L-Arginine is by the body into nitric oxide. Nitric oxide causes blood vessels to open wider for improved blood flow. L-arginine also stimulates the release of growth hormone, insulin, and other substances in the body. Increased strength through building muscle mass is not the only benefit of L-arginine for bodybuilding. By serving as a precursor for the vasodilator, nitric oxide, L-arginine promotes endurance and muscle conditioning. When nitric oxide is released, it widens the blood vessels by relaxing the muscles of their walls. This lowers blood pressure and increases blood flow to the muscles during workouts. The increased blood flow means that oxygen and nutrients are adequately supplied to your muscles and for longer amounts of time. This can help reduce muscle damage, promote healing and provide peak performance.